The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.
As seen from the northern hemisphere, meteor rates continue to be strong in November. While no major activity is expected this month, the two Taurid radiants plus the Leonids keep the skies active. The addition of strong sporadic rates make November one of the better months to view meteor activity from north of the equator. Skies are fairly quiet as seen from the southern hemisphere this month. Activity from the three showers mentioned above may be seen from south of the equator, but the sporadic rates are much lower than those seen in the northern hemisphere.
During this period the moon wanes from its last quarter phase to nearly new at the end of the period. This weekend the half illuminated last quarter moon will rise near 0100 LDT (Local Daylight Time) and will remain in the sky the remainder of the night. While the moon at this phase is still bright, it is nowhere as bright as the full moon encountered the previous week. Successful meteor observations can be undertaken by simply keeping the moon far from your field of view. The observing situation improves further as the week progresses as the moon wanes and rises later and later during the morning hours. The estimated total hourly rates for evening observers this week is near six from the northern hemisphere and three for observers south of the equator. For morning observers the estimated total hourly rates should be near twenty from the northern hemisphere and twelve as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Morning rates are reduced this week due to lunar interference.
The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning October 30/31. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The following showers are expected to be active this week:
Northern Taurids (NTA)
The center of the large Northern Taurid (NTA) radiant lies at 03:12 (048) +21. This area of the sky is located in eastern Aries, ten degrees southwest of the famous naked eye open cluster known as the Pleiades. The radiant is best placed near 0200 local daylight time (LDT), when it lies highest above the horizon. This shower peaks on November 13, so rates are slowly increasing. Current rates would be near two per hour, no matter your location. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. This shower is also responsible for many of the fireball reports seen in November.
Southern Taurids (STA)
The center of the large Southern Taurid (STA) radiant lies at 03:16 (049) +12. This area of the sky is located in eastern Aries, fifteen degrees southwest of the Pleiades. The radiant is also best placed near the meridian near 0200 LDT. We are now well past the October 10 maximum for this shower but rates will still remain near two per hour, no matter your location. Striking the atmosphere at 29 km/sec., the average Southern Taurid meteor travels slowly through the skies. This shower is also responsible for many of the fireball reports seen in October.
Eta Taurids (ETT)
Studies of the IMO video database by Sirko Molau and Juergen Rendtel has revealed a radiant located in Taurus this time of year. The Eta Taurids (ETT) are active from October 25 through November 3, with maximum occurring on October 25th. The current radiant position lies at 04:04 (061) +24, which lies in western Taurus, three degrees east of the Pleiades star cluster. The radiant is best placed near 0300 LDT, when it lies highest above the horizon. Meteors from the Eta Taurids strike the atmosphere at 47km/sec., which would produce meteors of average velocity. Expected rates would be less than one per hour, no matter your location.
The Orionids (ORI) reached maximum activity on October 22nd. Some activity may still be seen during the morning hours from a radiant located at 06:48 (102) +16. This position lies in southwestern Gemini, close to the second magnitude star Alhena (Gamma Geminorum). The radiant is best placed on the meridian near 0500 LDT. Current rates should be near three per hour no matter your location. At 67km/sec., the average Orionid is swift.
Beta Cancrids (BCN)
Another shower derived from the IMO video database is the Beta Cancrids (BCN). This shower is active from October 25-November 3 with a peak on the 27th. This shower has been known from visual observations for some time. Video analysis have confirmed the activity but from a slightly different portion of the sky. The radiant was suspected to be active from the Cancer/Gemini border when in fact the position actually lies in the constellation of Monoceros, to the south. The radiant is located at 07:32 (113) -10, which is fifteen degrees south of the brilliant zero magnitude star Procyon (Alpha Canis Minoris). The radiant is best placed during the last dark hour before dawn when it lies highest above the horizon in a dark sky. Rates should less than one per hour. With an entry velocity of 65 km/sec., most activity from this radiant would be swift.
Shower Name RA DEC Vel Rates km/s NH SH NTA Northern Taurids 02h 28m +18 29 1 1 STA Southern Taurids 01h 20m +06 30 2 2 ETT Eta Taurids 04h 04m +24 47 <1 <1 ORI Orionids 06h 08m +16 67 3 3 BCN Beta Cancrids 07h 32m -10 65 <1 <1 RA - Right Ascension DEC - Declination Vel - Velocity relative to Earth (in km per sec) Rates - Rate of visible meteors per hour from a dark site NH - Northern Hemisphere SH - Southern Hemisphere